Bi_2Ti_2O_7/TiO_2异质结对盐酸四环素的光催化降解效果评价

Photocatalytic Degradation of Tetracycline Hydrochloride Using Bi_2Ti_2O_7/TiO_2 Heterojunction

采用溶剂热法通过控制溶剂比获得3种不同形貌的Bi_2Ti_2O_7/TiO_2异质结(BT-0、BT-5、BT-10).采用X射线衍射仪(XRD)、场发射扫描电子显微镜(SEM)、低温氮气吸附-脱附(BET)、Zeta电位仪和循环伏安实验等对催化剂的晶型结构、形貌和性能进行表征.研究了异质结对盐酸四环素(TC)的吸附和光催化降解性能,考察了溶液的初始p H、盐酸四环素的初始浓度和催化剂投加量对盐酸四环素光催化降解效率的影响.实验结果表明,橄榄球状Bi_2Ti_2O_7/TiO_2异质结具有更大的比表面积和较多孔型,对盐酸四环素的吸附去除率更大.在异质结加入量为0.1 g/L,250 W金卤灯下反应180 min,BT-0、BT-5和BT-10异质结对浓度为0.05 g/L初始pH为8.9的盐酸四环素去除率分别为92.4%、99.8%、97%.异质结对盐酸四环素的光降解反应符合拟一级动力学规律.

The different morphologies Bi2Ti207/Ti0 2 heterojunction （ BT-0, BT-5, BT-10） were synthesized by a simple glycerol-assisted alcoholthermal method via control of the volume ratio of glycerol and ethanol. The as-prepared Bi2Ti207/Ti02 composites were characterized by XRD, FESEM, Zeta potential and cyclic voltammetry. The adsorption and photocata-lytic degradation of tetracycline （TC） were studied by Bi2Ti207/Ti02 under the simulated sunlight. The influences of initial pH, the concentration and the amount of catalyst on the removal efficiency of TC were investigated. The results showed that the highest removal rate was performed by the rugby structure Bi2Ti207/Ti02 heterojunction（ BT-5） with high specific area and pore types. The removal efficiency of 0.05 g/L TC reached 92.4%,99.8% and 97% respectively with 1 g/L BT-0,BT-5 and BT-10 heterojunction and 3h irradiation under irradiation of a 250W halogen lamp and the initial pH of TC solution 8.9. The degradation of TC using Bi2Ti207/Ti02 heterojunction obeys the law of apparent first-order dynamics reaction.